Powertrain architecture for a vehicle utilizing an on-board charger

ABSTRACT

Techniques related to powertrain architectures for vehicles (such as hybrid electric vehicle/electric vehicles) utilizing an on-board charger are disclosed. The techniques include a device for power regulation, the device comprising a direct current (DC)-to-DC voltage converter configurable to convert a first DC voltage from an alternating current (AC)-to-DC converter to generate a first converted DC voltage to charge a battery, and convert a second DC voltage from the battery to a second converted DC voltage for a DC-to-AC inverter. The inverter couples to a motor. A control circuit is configured to direct an operating mode of the voltage converter.

This application is a divisional of U.S. patent application Ser. No.16/236,556, filed Dec. 30, 2018, which will issue as U.S. Pat. No.11,376,977 on Jul. 5, 2022, the entire content of which is incorporatedherein by reference.

BACKGROUND

Hybrid electric vehicles (HEV) and electric vehicles (EV) are increasingin popularity as they offer reduced fuel costs and lower vehicleemissions as compared to conventional internal combustion enginepropelled vehicles. HEV/EVs are powered using one or more batteriesdriving one or more electrical motors. HEVs may be driven by motors andbatteries used in conjunction with a conventional internal combustionengine. EVs are driven purely by motors and batteries.

Both HEVs and EVs consume large amounts of electricity, and thiselectricity is generally stored in one or more batteries. Thesebatteries may be charged using a combination of regeneration using themotor acting as an electrical generator, or, when the vehicle is not inuse, by an electric charger and external power source. The electriccharger traditionally has come in on-board and off-board varieties.Off-board charging generally refers to charging systems utilizing acharging station or other equipment, such as a home or wall charger.These systems traditionally offer higher voltages and faster chargingthan traditional on-board charging systems, which utilize a charger buntinto the car itself. Increasingly, to provide flexibility and increasedconvenience, higher capacity on-board chargers are offering increasedcharging speeds.

SUMMARY

This disclosure relates generally to the field of HEV/EVs. Moreparticularly, but not by way of limitation, aspects of the presentdisclosure relates to device for power regulation. The device comprisesa direct current (DC)-to-DC voltage converter configurable to convert afirst DC voltage from an alternating current (AC)-to-DC converter togenerate a first converted DC voltage to charge a battery. The devicefurther converts a second DC voltage from the battery to a secondconverted DC voltage for an inverter, the inverter electrically coupledto a motor, along with control circuitry for directing an operating modeof the DC-to-DC voltage converter.

Another aspect of the present disclosure relates to a system for powerregulation. The system comprises a direct current (DC)-to-DC voltageconverter having two operating modes, wherein the DC-to-DC voltageconverter, in a first operating mode, converts a first DC voltage froman alternating current (AC)-to-DC converter to generate a firstconverted DC voltage to charge a battery. The DC-to-DC voltageconverter, in a second operating mode, converts a second DC voltage fromthe battery to a second converted DC voltage for an inverter, theinverter electrically coupled to a motor. The system further comprisescontrol circuitry for directing an operating mode of the DC-to-DCvoltage converter.

Another aspect of the present disclosure relates to a method for powerregulation of a bus. The method comprises converting, by a directcurrent (DC)-to-DC voltage converter in a first operating mode, a firstDC voltage at a regulated voltage from an AC-to-DC converter to generatea first converted DC voltage to charge a battery. The method furthercomprises converting, by the DC-to-DC voltage converter in a secondoperating mode, a second DC voltage from the battery, the second DCvoltage having a variable voltage to generate a second converted DCvoltage at the regulated voltage for an inverter that is electricallycoupled to a motor.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various examples, reference will now bemade to the accompanying drawings in which:

FIGS. 1-4 are architectural diagrams illustrating vehicle powertrains,in accordance with aspects of the present disclosure.

FIG. 5 is a circuit diagram of a power factor correction circuit, inaccordance with aspects of the present disclosure.

FIG. 6 is an architecture diagram illustrating at least a portion of avehicle powertrain, in accordance with aspects of the present disclosure

FIG. 7 is a circuit diagram illustrating an example DC-to-DC voltageconverter circuit, in accordance with aspects of the present disclosure.

FIG. 8 is a flow diagram illustrating a technique for power regulationof a bus, in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Powertrains for HEV/EV vehicles generally include one or more batterypacks (hereinafter referred to as battery). The battery may be chargedusing an on-board charger (OBC) built into the vehicle. One function ofthe OBC is to convert power received from a power grid from analternating current (AC) form to a direct current (DC) form, and toprovide the DC power to charge the battery. For example, the OBC may beplugged into a wall outlet and draw power from a public utility powergrid to charge the vehicle battery. The OBC may include an AC-to-DCconverter (also known as a rectifier) that accepts an input AC voltage,such as 120 VAC, 240 VAC, 480 VAC, etc. from a wall socket and generatesan output DC voltage at a first DC voltage. In certain cases this firstDC voltage may not be suitable or efficient for charging the battery andthe OBC may also include a second stage comprising a DC-to-DC voltageconverter which converts the first DC voltage into a second DC voltage,which is more suitable for charging the battery.

In certain cases, the DC-to-DC converter and AC-to-DC converter used inthe OBC support bidirectional operation. For example, vehicle-to-grid(V2G) operations may allow a power grid to draw electricity from chargedbatteries of HEV/EV vehicles to support the power grid. In such cases,the DC-to-DC voltage converter may be configured to draw power from thebattery and convert the first DC voltage of the battery to a second DCvoltage that the AC-to-DC converter can handle. The AC-to-DC converterthen converts the second DC voltage to AC, to send back to the grid.

The powertrain may also include a traction inverter to convert DCvoltage from the battery into AC voltage. The traction inverter thenprovides this AC voltage to one or more electric motors to drive thevehicle. Generally a voltage provided by the battery varies as thebattery discharges. Typically the traction inverter takes into accountthis voltage change and is designed to handle a wide voltage range of DCvoltage input that the battery may provide. This ability to handle awide input voltage range makes the traction inverter less efficient atconverting DC-to-AC as compared to an inverter that has a regulatedinput voltage. For example, an inverter designed for a regulated inputvoltage may utilize a design or components selected to operate mostefficiently at the regulated voltage. As discussed herein, reference toa regulated or fixed voltage refers to a constant voltage within adesign tolerance of the converter providing the regulated voltage.

Additionally, other devices, such as on-board computers, adjustablesuspension systems, entertainment systems, etc., may utilize electricityprovided by the battery. These devices may be isolated from the changingbattery voltage on separate electrical busses (such as a 12 v or 48 vbus) driven by other DC-to-DC voltage converters. Such DC-to-DC voltageconverters may also be designed to handle the changing battery voltage,making them potentially less efficient than converters designed to takea particular input voltage.

FIG. 1 is an architectural diagram illustrating at least a portion of avehicle powertrain 100, in accordance with aspects of the presentdisclosure. In the example vehicle powertrain 100, an OBC 102 is, in acharging operating mode, coupled to an AC power source 104, such as alocal power grid. In some cases, the OBC 102 is a two stage charger andincludes an AC-to-DC converter 106 and a charger DC-to-DC voltageconverter 108 within an OBC housing 109. The AC-to-DC converter 106converts the AC voltage from AC power source 104 to a first DC voltageand provides this first DC voltage via conductor 111 to the chargerDC-to-DC voltage converter 108 to generate a DC voltage at a regulatedvoltage to drive a variable DC bus 112. In certain cases, the OBC 102may include a cooling mechanism 110, such as a heatsink, fans, coolantlines, etc. The cooling mechanism 110 may be at least partiallyincorporated into the OBC housing 109 and the exact mechanism used maybe a function of a number of factors such as packaging constraints,efficiency of the OBC 102, or other factors. The cooling mechanism maybe configured to reduce an operating temperature of either, or both, theAC-to-DC converter 106 and the charger DC-to-DC voltage converter 108.The DC voltage provided by the OBC 102 energizes the variable DC bus 112and charges a battery 114 coupled to the variable DC bus 112.

In certain cases, the OBC 102 operates in multiple modes. For example, acontrol circuit 116 of the OBC 102 detects when the AC power source 104is plugged in or otherwise becomes available, and responds by switchingthe OBC 102 into the charging operating mode. An AC power indicatorsignal 105 is shown in FIG. 1. The AC power indicator signal 105indicates to the control circuit 116 whether the OBC 102 is connected tothe AC power source 104. The control circuit 116 may also receive anindication, for example from the power grid, to provide power to thegrid. The control circuit 116 of the OBC 102 can then switch the OBC 102into a V2G operating mode to possibly provide power back to the gridthrough AC power source 104. In general, the control circuit 116configures the DC-to-DC voltage converter 108 to convert a DC voltagefrom the AC-to-DC voltage converter 106 to a voltage for the variable DCbus 112, or vice versa. The control circuit 116 may be implemented as aprogrammable processor, a finite state machine, or other suitable typeof circuit. When the AC power source 104 is not plugged in or available,the control circuit 116 may switch the OBC 102 into a driving operatingmode. Generally, the charging and V2G operating modes arenon-overlapping.

In the driving operating mode, the battery 114 energizes the variable DCbus 112, to thereby provide power to a traction inverter 118 as well asone or more body electronics 120. In the example of FIG. 1, bodyelectronics 120 are coupled to, and receive power from, a bodyelectronics bus 124, which may operate at lower voltages than thevariable DC bus 112. As an example, an entertainment system or poweradjustable seats may operate at 12 v or 48 v rather than the highervoltages typically provided by a HEV/EV battery. One or more bodyDC-to-DC voltage converters 122 converts the DC voltage of the variableDC bus 112 to another DC voltage appropriate for the body electronics120 on a corresponding body electronics bus 124. For example, differentvehicle electronics may operate at different DC voltages or may be moresensitive to voltage fluctuations, noise, etc., and additional bodyDC-to-DC voltage converters (not shown) may be attached to the variableDC bus 112 as needed to segregate these components on separateelectrical buses.

In the driving operating mode, the traction inverter 118 also drawspower from the variable DC bus 112 to drive one or more traction motors126. The traction inverter 118 converts DC to AC in two stages using aDC-to-DC voltage converter 128 first stage coupled to a DC-to-ACinverter 130 second stage. As the capacity of the battery 114 is drawndown, the voltage across the variable DC bus 112 may change. TheDC-to-DC voltage converter 128 converts the variable DC voltage of thevariable DC bus 112 to a regulated DC voltage and provides this voltagefor the DC-to-AC inverter 130 via conductor 131. The DC-to-AC inverter130 converts this regulated DC voltage to AC to drive traction motor126.

In some cases, the two stage conversion of DC-to-DC cascaded with theDC-to-AC traction inverter 118 is more efficient for a motor drive thana single stage inverter, since converting a variable DC voltage to adesired DC voltage can be performed quite efficiently, in some casesgreater than 98% efficient. The DC-to-AC inverter 130 may then beoptimized for efficiency at the desired DC voltage, for example, byhaving the switching scheme optimized in an inverter control to reduceits switching loss, to drive motor more efficient for high speed runningwithout the need for field-weakening control In motor drive. Theincreased efficiency realized by optimizing the DC-to-AC inverter 130outweighs the losses from the DC-to-DC conversion stage and using a twostage conversion of DC to AC reduces losses as compared to a singlestage DC to AC conversion given a relatively large input DC voltagerange.

The traction inverter 118 in this example also includes an invertercooling mechanism 132, such as a heatsink, fans, coolant lines, etc. Theinverter cooling mechanism 132 may also be least partially incorporatedinto the traction inverter 118 housing and may be configured to reducean operating temperature of either, or both, the inverter DC-to-DCvoltage converter 128 and the DC-to-AC inverter 130. The invertercooling mechanism may be similar to cooling mechanism 110. It may beobserved that OBC 109 and traction inverter 118 run in alternativemodes. That is, when OBC 109 is running in an active mode, the tractioninverter 119 will be in an idle mode and vice versa.

FIG. 2 is another example of at least a portion of a vehicle powertrain200. Adding a DC-to-DC voltage converter to a traction inverter improvesefficiency but potentially increases the size and cooling requirementsfor the traction inverter. To help address these constraints, theDC-to-DC voltage converter from the OBC may be leveraged to provide aregulated DC voltage for the traction inverter. Generally the chargerDC-to-DC voltage converter does not convert power from the power grid toand from the battery at once as vehicles are generally are not drivenwhile plugged in and charging. Using the charger DC-to-DC voltageconverter to provide a regulated DC voltage for the traction inverterthus is unlikely to interfere with charging the battery.

In the example vehicle powertrain 200, an OBC 202 is, in a chargingmode, coupled to an AC power source 204, such as a local power grid. Inthis example, OBC 202 is a two stage charger and includes an AC-to-DCconverter 206 and a DC-to-DC voltage converter 208 within an OBC housing209. During charging, the AC-to-DC converter 206 converts the AC voltagefrom the AC power source 204 to a first DC voltage and provide thisfirst DC voltage to the DC-to-DC voltage converter 208 via a regulatedDC bus 222. The DC-to-DC voltage converter 208 generates a second DCvoltage to drive a variable DC bus 214 and charge a battery 210 coupledto the variable DC bus 214. The OBC 202 may include a cooling mechanism212 that may be at least partially incorporated into the OBC housing209. The cooling mechanism 212 is discussed in more detail above inconjunction with cooling mechanism 110 of FIG. 1.

For switching from the charging operating mode to the driving operatingmode, control circuit 216 of the OBC 102 can determine that the AC powersource 104 is not plugged in, receive an indication to switch to adriving operating mode, for example from a vehicle control computer (notshown), or otherwise detect that the AC power source is unavailable. Forexample, an AC power indicator signal 217 indicates to the controlcircuit 216 that the OBC 202 is not connected to the AC power source204. The control circuit 216 can then switch the DC-to-DC voltageconverter 208 to the driving operating mode and accept input power fromthe battery 210 rather than from the AC-to-DC converter 206. During aregen operation, the control circuit 216 may receiving an indication toswitch to the charging operating mode and switch the DC-to-DC voltageconverter 208 to convert voltage from a DC-to-AC inverter 218 of atraction inverter 220 to provide power to charge battery 210 over thevariable DC bus 214. In certain cases, the DC-to-AC inverter may beconfigured to generate DC voltage at the regulated DC voltage, duringregen operation. While the control circuit 216 is shown outside of theOBC housing 209, it should be understood that the control circuit 216may also be located within or on the OBC housing 209.

The DC-to-DC voltage converter 208 converts the variable DC voltage,provided by battery 210, of the variable DC bus 214 to a regulated DCvoltage for the regulated DC bus 222. The DC-to-AC inverter 218 of thetraction inverter 220 receives power from the regulated DC bus 222 atthe regulated DC voltage and converts this regulated DC voltage to AC todrive the traction motor 224. The traction inverter 220 may also includean inverter cooling mechanism 226 which may also be least partiallyincorporated into a traction inverter housing 228.

One or more body DC-to-DC voltage converters 232 convert the DC voltageof the variable DC bus 214 to another DC voltage appropriate for one ormore body electronics 230. As shown in FIG. 3, in certain cases, one ormore regulated body DC-to-DC voltage converters 302 draw power from aregulated DC bus 304 and convert the regulated DC voltage to another DCvoltage appropriate for one or more body electronics 306. As theregulated body DC-to-DC voltage converters 302 draw from a regulated DCvoltage, the regulated body DC-to-DC voltage converters 302 may bedesign optimized for efficiency at the regulated DC voltage, helpingfurther increase overall efficiency of the vehicle. In certain cases,one or more body DC-to-DC voltage converters 308 also draw from avariable DC bus 310 for one or more body electronics 316. Controlcircuit 312 can switch operating modes for a DC-to-DC voltage converter314 based on, for example, an AC power indicator or another indicator.

In certain embodiments, the OBC 202 includes the AC-to-DC converter 206within an OBC housing 209 and the DC-to-DC voltage converter 208incorporated into the traction inverter 220 within the traction inverterhousing 228. The control circuit 216, in such embodiments, are coupledto the DC-to-DC voltage converter 208 incorporated into the tractioninverter 220.

FIG. 4 is another example of at least a portion of a vehicle powertrain400, in accordance with aspects of the present disclosure. In thisexample, the OBC and the traction inverter are packaged together in as acombined unit within a common housing to help reduce the physical spacetaken up by these components and potentially reduce the number ofcooling mechanisms.

In the vehicle powertrain 400, a combined unit 402 may be coupled to anAC power source 404 while in a charging operating mode. The combinedunit includes an AC-to-DC converter 406 to convert AC voltage from theAC power source 404 to a first DC voltage and provides this first DCcurrent via a regulated DC bus 408. In certain cases, this first DCvoltage is at a regulated voltage of the regulated DC bus 408. ADC-to-DC voltage converter 410 within a combined unit housing 417converts this first DC voltage to a second DC voltage and provides thissecond DC voltage to a variable DC bus 412 to charge battery 414. ADC-to-AC inverter 416 can be at least partially enclosed within thecombined unit housing 417. A cooling mechanism 418 is at least partiallyincorporated into the combined unit housing 417 and is configured toreduce the operating temperature of one or more of the AC-to-DCconverter 406, the DC-to-DC voltage converter 410, and the DC-to-ACinverter 416.

A control circuit 420 switches the DC-to-DC voltage converter 410 fromthe charging operating mode to a driving operating mode. In the drivingoperating mode, the DC-to-DC voltage converter 410 draws power from thebattery 414, rather than from the AC-to-DC converter 406, over thevariable DC bus 412. The DC-to-DC voltage converter 410 converts thevariable DC voltage to the regulated DC voltage and provides theregulated DC voltage to a regulated DC bus 408. The DC-to-AC inverter416 converts the regulated DC voltage, from the regulated DC bus 408, toAC to drive the traction motor 422. While the control circuit 420 isshown outside of the combined unit housing 417, it should be understoodthat the control circuit 420 may also be located within the combinedunit housing 417.

One or more body DC-to-DC voltage converters 424 draws from the variableDC bus 412 to convert the DC voltage of the variable DC bus 412 toanother DC voltage appropriate for certain body electronics (not shown).One or more regulated body DC-to-DC voltage converters 426 draw powerfrom a regulated DC bus 408 and convert the regulated DC voltage toanother DC voltage appropriate for one or more body electronics (notshown).

FIG. 5 is a circuit diagram of an example power factor correctioncircuit 500, in accordance with aspects of the present disclosure.Generally, an AC-to-DC converter 502 includes some passive components504, such as inductors (as shown in this example), inductor capacitor,or inductor capacitor inductor, as well as an AC-to-DC bridge structure508. The passive components connect to the AC-to-DC bridge structure 508to form the full AC-to-DC converter. For example, AC-to-DC converters106, 206, and 406 of FIGS. 1, 2, and 4, respectively, include passivecomponents 504 and the AC-to-DC bridge structures 508. In this example,three different voltages from an AC power source 506 may be connected tothe passive components 504 to form a three phase power factor correction(PFC) (as shown). In certain cases two phases may include passivecomponents and one phase might not have a passive component for a singlephase PFC (not shown). In other cases, a mux version may be offered tosupport both single phase and three phase PFC (not shown). The AC-to-DCbridge structure 508 and passive components 504 work together togenerate a regulated bus at the output of the AC-to-DC converter 510. Incertain cases, the AC-to-DC bridge structure 508 for a typical threephase inverter comprises three half bridges 512. The half bridges 512are controlled by control circuitry (not shown) to regulate the currentthrough each phase. The control is achieved by turning on and tuning offthe power devices of the half bridges 512. Duty cycle regulation istypically used, in which the converter in the AC-to-DC mode for PFC, theAC-to-DC bridge structure 508 behaves as a boost circuit. When operatingin the DC-AC mode for motor control, the AC-to-DC bridge structure 508behaves as a buck circuit. While, in the example, a two level threephase inverter structure is shown in the AC-to-DC bridge structure 508,the two level three phase inverter structure can be replaced with athree level or a different inverter structure.

FIG. 6 is an architecture diagram illustrating at least a portion of avehicle powertrain 600, in accordance with aspects of the presentdisclosure. In this example, functionality of the OBC and tractioninverter are integrated into a combined unit 602, which is at leastpartially contained within a combined housing 604.

In the vehicle powertrain 600, the combined unit 602 may be coupled toan AC power source 606 while in a charging operating mode. The combinedunit 602 may include passive components 608 needed for the AC-to-DCstage, an AC-to-DC converter components (including associated bridgestructure, sense electronics, and control circuitry) 610, and a DC-to-DCvoltage converter 614. The AC voltage from the AC power source 606 isconnected to the passive components 608 and provided to the AC-to-DCconverter components 610, to convert AC voltage from the AC power source606 to the first DC voltage. In a manner similar to that shown in FIG.4, the first DC voltage is provided via a DC regulated bus 612 to theDC-to-DC voltage converter 614 to charge battery 616 via a variable DCbus 618. Switch 620 may be coupled between a traction motor 622 and aconnection point of the passive components 608 and the AC-to-DCconverter components 610. In this case, the AC-to-DC convertercomponents 610 may comprise a three phase half bridge inverter capableof operating as an active PFC as well as a traction drive, depending onthe operating mode. During charging, switch 620 is open and a tractionmotor 622 is not powered. While a single switch 620 is shown, it can beunderstood that switch 620 may comprise three switches, one for eachphase line coupled to the motor. The passive components 608, AC-to-DCconverter components 610, and DC-to-DC voltage converter 614 can be atleast partially enclosed within the combined housing 604. A coolingmechanism 624 is at least partially incorporated into the combinedhousing 604 and is configured to reduce the operating temperature of oneor more of the AC-to-DC converter components 610, the DC-to-DC voltageconverter 614, and the passive components 608.

A control circuit 626 switches the DC-to-DC voltage converter 614 andthe AC-to-DC converter components 610 from the charging operating modeto a driving operating mode. While the control circuit 626 is shownoutside of the combined housing 604, it should be understood that thecontrol circuit 626 may also be located within the combined housing 604.

In the driving operating mode, the DC-to-DC voltage converter 614 drawspower from the battery 616, rather than from the AC-to-DC convertercomponents 610, over the variable DC bus 618. The DC-to-DC voltageconverter 614 converts the variable DC voltage to the regulated DCvoltage and provides the regulated DC voltage to a regulated DC bus 612.Though in certain embodiments, the battery voltage may directly be usedby the AC-to-DC converter components 610 over the variable DC bus 618.The AC-to-DC converter components 610, in the driving operating mode,converts the regulated DC voltage, from the regulated DC bus 612, to ACto drive the traction motor 622. When in an operating mode other thanthe charging operating mode, the passive components 608 are opencircuits and are unaffected by power from the AC-to-DC convertercomponents 610 or traction motor 622.

One or more body DC-to-DC voltage converters 628 draws from the variableDC bus 618 to convert the DC voltage of the variable DC bus 618 toanother DC voltage appropriate for certain body electronics (not shown).One or more regulated body DC-to-DC voltage converters 630 draw powerfrom a regulated DC bus 612 and convert the regulated DC voltage toanother DC voltage appropriate for one or more body electronics (notshown).

FIG. 7 is a circuit example of the DC-to-DC voltage converter 700circuit usable in the examples described above (e.g., for DC-to-DCvoltage converters 108, 208, 314, and 410). The DC-to-DC voltageconverter 700 is a bi-directional voltage converter and is controlled bya control circuit (control circuit 116, 216, 312, 420, and 614). In afirst mode, the corresponding control circuit configures thebidirectional DC-to-DC voltage converter 700 to accept input power froma first voltage node 710 and output converted power to a second voltagenode 720. In a second mode, the control circuit configures the DC-to-DCvoltage converter 700 to accept input power from the second voltage node720 and output converted power to the first voltage node 710.

Referring still to FIG. 7, the bi-directional DC-to-DC voltage converter700 includes transistors M1, M2, M3, M4, M5, M6, M7 and M8, inductor L1,and transformer TR1. The transistors are implemented as n-channel metaloxide semiconductor field effect transistors (NMOS), but can beimplemented as p-channel metal oxide semiconductor field effecttransistors (PMOS) in other implementations, or as bipolar junctiontransistors in yet other implementations. Each transistor M1-M6 includesa control input (e.g., a gate) that is controlled by the correspondingcontrol circuit to turn that respective transistor on or off dependingon the operating mode. M1, M2, M3 and M4 form a first full bridge andM5, M6, M7 and M8 for a second full bridge. Both duty cycle control andphase control of M1-M8 are used to control and regulate the power flow.

FIG. 8 is a flow diagram illustrating a technique 800 for powerregulation of a bus, in accordance with aspects of the presentdisclosure. At block 802, a DC-to-DC voltage converter in a firstoperating mode converts a first DC voltage at a regulated voltage froman AC-to-DC converter to generate a first converted DC voltage to chargeone or more batteries. At block 804, the Dc-to-DC voltage converter isin a second operating mode and converts a second DC voltage from thebatteries to generate a second converted DC voltage at the regulatedvoltage for an inverter that is electrically coupled to a motor. Thesecond DC voltage has a variable voltage that may vary based on thecharge level of the batteries. At block 806, the Dc-to-DC voltageconverter is in a second operating mode and generates the secondconverted DC voltage for a second DC-to-DC voltage converter to convertthe second converted DC voltage to a third DC voltage different from theregulated voltage.

In this description, the term “couple” or “couples” means either anindirect or direct wired or wireless connection. Thus, if a first devicecouples to a second device, that connection may be through a directconnection or through an indirect connection via other devices andconnections. The recitation “based on” means “based at least in parton.” Therefore, if X is based on Y, X may be a function of Y and anynumber of other factors.

Modifications are possible in the described embodiments, and otherembodiments are possible, within the scope of the claims.

1. A system comprising: a switch including a first terminal configuredto be coupled to a traction inverter, wherein the switch furtherincludes a second terminal configured to be coupled to analternating-current (AC) power source; a regulated bus; anAC/direct-current (AC/DC) converter including a first set of terminalscoupled to the second terminal of the switch, wherein the first set ofterminals of the AC/DC converter is configured to be coupled to the ACpower source, wherein the AC/DC converter further includes a second setof terminals coupled to the regulated bus; a variable bus configured tobe coupled to a battery; and a first DC/DC converter including a firstset of terminals coupled to the regulated bus, wherein the first DC/DCconverter further includes a second set of terminals coupled to thevariable bus.
 2. The system of claim 1, further comprising a third DC/DCconverter including a first set of terminals coupled to the regulatedbus.
 3. The system of claim 2, wherein the third DC/DC converter furtherincludes a second set of terminals configured to be coupled to one ormore body electronics.
 4. The system of claim 1, further comprising asecond DC/DC converter including a first set of terminals coupled to thevariable bus.
 5. The system of claim 4, wherein the second DC/DCconverter further includes a second set of terminals configured to becoupled to one or more body electronics.
 6. The system of claim 1,further comprising one or more passive components coupled to the secondterminal of the switch, wherein the one or more passive components arecoupled to the first set of terminals of the AC/DC converter, andwherein the one or more passive components are configured to be coupledto the AC power source.
 7. The system of claim 6, wherein the switch isconfigured to operate as a first open circuit when the system is in acharging operating mode, and wherein the one or more passive componentsare configured to operate as a second open circuit when the system is inan operating mode other than the charging operating mode.
 8. The systemof claim 1, further comprising a combined housing at least partiallyenclosing the switch, the AC/DC converter, and the first DC/DCconverter.
 9. The system of claim 8, further comprising a coolingmechanism at least partially incorporated into the combined housing. 10.The system of claim 1, further comprising the traction inverter coupledto the first terminal of the switch.
 11. The system of claim 1, furthercomprising the battery coupled to the second set of terminals of thefirst DC/DC converter.
 12. A vehicle comprising: a traction inverter; aswitch including a first terminal configured to be coupled to thetraction inverter, wherein the switch further includes a second terminalconfigured to be coupled to an alternating-current (AC) power sourceexternal to the vehicle; a regulated bus; an AC/direct-current (AC/DC)converter including a first set of terminals coupled to the secondterminal of the switch, wherein the first set of terminals of the AC/DCconverter is configured to be coupled to the AC power source, whereinthe AC/DC converter further includes a second set of terminals coupledto the regulated bus; a battery; a variable bus configured to be coupledto the battery; and a first DC/DC converter including a first set ofterminals coupled to the regulated bus, wherein the first DC/DCconverter further includes a second set of terminals coupled to thevariable bus.
 13. The vehicle of claim 12, further comprising a thirdDC/DC converter including a first set of terminals coupled to theregulated bus.
 14. The vehicle of claim 13, wherein the third DC/DCconverter further includes a second set of terminals configured to becoupled to one or more body electronics.
 15. The vehicle of claim 12,further comprising a second DC/DC converter including a first set ofterminals coupled to the variable bus.
 16. The vehicle of claim 15,wherein the second DC/DC converter further includes a second set ofterminals configured to be coupled to one or more body electronics. 17.The vehicle of claim 12, further comprising one or more passivecomponents coupled to the second terminal of the switch, wherein the oneor more passive components are coupled to the first set of terminals ofthe AC/DC converter, and wherein the one or more passive components areconfigured to be coupled to the AC power source.
 18. A systemcomprising: a regulated bus; a variable bus configured to be coupled toa battery; an alternating-current/direct-current (AC/DC) converterincluding a first set of terminals configured to be coupled to an ACpower source; a first DC/DC converter including a first set of terminalscoupled to the regulated bus, wherein the first DC/DC converter furtherincludes a second set of terminals coupled to the variable bus; and asecond DC/DC converter including a first set of terminals coupled to theregulated bus, wherein the first set of terminals of the AC/DC converteris configured to be coupled to a traction inverter, and wherein theAC/DC converter further includes a second set of terminals coupled tothe regulated bus.
 19. The system of claim 18, further comprising athird DC/DC converter including a first set of terminals coupled to thevariable bus, wherein the third DC/DC converter further includes asecond set of terminals configured to be coupled to one or more bodyelectronics.
 20. The system of claim 18, further comprising a combinedhousing at least partially enclosing the AC/DC converter and the firstDC/DC converter.